Grinding-machine.



" H.- B. N'IGHQLS.

GRINDING MAOEINB. APPLIGATIOH mum Mn 27 1910,

Patented Jan,3,1911.

a wumvi o-z GRINDING-MAOHINE.

UNITED STATES PATENT QFFICE.

HENRY B. NICHOLS, OF PHILADELPHIA, PENNSYLVANIA.

Patented Jan. 3, 1911.

Original application filed December 27, 1909, Serial No. 535,091.Divided and this application filed May 27,

To all whom it may concern:

Be it known that I, HENRY B. Nlor-roLs, a citizen of the United States,residing at Philadelphia, county of Philadelphia, and State ofPennsylvania, have invented certain new and useful Improvements inGrinding-Machines, of which the following is a specification, referencebeing had therein to the accompanying drawing.

My invention relates to grinding machines and especially to certainforms of grinding wheels, for use in said machines.

This application is a division of my prior application, Serial No.535,091, filed December 27, 1909, which in turn is a division of each oftwo prior applications, Serial No. 451,875, filed September 5, 1908,patented December 28,1909,PatentNo. $14,902; and Serial No. 472,236,filed January 1 1, 1909, patented December 28, 1909, Patent No. 944,903.In the two patented cases the claims are directed to grinding machinessuch; in the prior application serial No. 535,091, I have claimed theautomatic calipers as such, and in the present case I shall direct myclaims to a grinding wheel with antifriction rings or inserts in itsface or back. I shall not claim herein the specific form of theinvention in which the inserts are set in the clamping plate instead ofin the body of the wheel, because that is claimed in my divisionalapplication, Serial No. 578,367, filed August 22, 1910.

My invention is illustrated in the accompanying drawings, in whichFigure 1 is a plan view of a portion of one of the machines shown in myprior patents and application aforesaid, showing the. calipers and partof a wheel. Fig. 2 is a face view of the wheel showing the ring inserts.Fig. 3 is a section thereof on the line 8-8 of Fig. 2. Fig. 1 is asectional view of a modification having the inserts in its back and Fig.5 is a sectional view of another modification having the inserts set inthe rear clamping plate instead of in the body of the wheel.

I will not attempt to describe in detail herein the machines to which mypresent invention is applied and with which it is used. For a fulldisclosure of said machines I refer to my aforesaid Patents Nos. 944,902and 944,903.

In Fig. 1, I have shown a portion of the calipering apparatus describedin my Pat- Serial No. 563,755.

the wheel IV is formed of abrasive material such as carborundum or thelike, properly shaped and with suitable fittings to secure it to thespindle. As it would be impracticable to apply automatic calipersdirectly to the surface of this abrasive material, I provide inserts inthe shape of annular bodies of anti-friction or lubricant material at 1and 2. The best material for this purpose which I have found up to thepresent time is graphite molded into channels or grooves in the wheels.One process of molding consists in mixing the graphite with water toform a thick paste, and then pressing this into the grooves so as toexpel as much of the water as possible, and evaporating the rest. Thisprocess, however, 1s not entirely reliable in its results because of theshrinkage of the paste in drying, unless constant and very heavypressure is employed, such as that obtainable by hydraulic means, withthe attendant danger of fracturing the wheel. I prefer, therefore, toemploy a binder which under ordinary conditions of temperature andpressure is a solid, and which can remain permanently incorporated withthe graphite. Such a binder I have found in sulfur, which does not seemto affeet the operation of the wheel or impair the efficiency of thegraphite for my purpose. This is first melted, and the powdered graphiteis stirred or ground into it in the proportion of two parts by weight ofgraphite to one of sulfur. The wheel body is then heated to a uniformtemperature of about 212 Fahrenheit, the paste is poured or pressed intothe grooves, and the whole allowed to cool. The two rings 1 and 2 thusformed present a smooth anti-friction snrface for the calipers,sufficiently hard for accurate dimensioning, while I have found that theinsert. will wear away uniformly with the surface of the abrasivematerial and will not deter the grinding by its lubricant qualities.

Fig. 1 shows the back of a wheel, with a ring of graphite composition 3,upon which the roller of the caliper bears. This ring may be similar tothose hereinbefore referred to, but held in an undercut or dovetailedrecess or groove. The composition I have employed for this ring when setinto the wheel body, is formed of powdered or fiake graphite held in abinder of sulfur. The sulfur is first melted, and the graphite isstirred or ground into it in the proportion of two parts by weight ofgraphite to one of sulfur. The wheel body having been prepared with thedovetailed recess as shown at a in Fig. at, is heated to a uniformtemper ature of about 212 Fahrenheit, the graphite paste is poured orpressed into the groove, and the body allowed to cool. In Fig. 5 I haveshown a modification in which the ring is set into the metal clampingplate on the back of the wheel. This arrangement has some advantages asfor example it enables pure graphite to be employed, inserted in thegroove under pressure. The ring can be made in several other ways, as byforming a paste of water, a gum solution, or the like. In

any case and whether set in the wheel body or the clamping plate, I findthat the undercut groove is of value in holding the ring in place, andas it constitutes an improvement over the former arrangement I shallclaim it herein.

Having thus described my invention what I claim and desire to secure byLetters Patent is 1. A grinding wheel of abrasive material with asurface insert of nomnetallic antifriction material.

2. A grinding wheel composed of abrasive material with a graphite ringset into its surface.

3. A grinding head having a body of abrasive material with an annularchannel or groove, and a mass composed of graphite and a. binder fillingsaid groove.

4. A grinding head having a body of abrasive material with an annularchannel or groove, and a composition of graphite and sulfur filling saidgroove.

5. A reducing tool for metal working 1na chines having a working faceand a deposit of nomnetallic antifriction material in its face.

6. A grinding wheel having an undercut or dovetail channel or grooveformed in its body, and a mass of nonmetallic and nonabrasive materialheld in said groove.

In testimony whereof I afiix my signature in presence of two witnesses.

HENRY B. NICHOLS.

\Vitnesses GEO. B. TAYLOR, L. E. Knorr.

